20
ABB i-bus
®
KNX
Functional description
Each DALI output (channel) of the DALI-Gateway DG/S 8.1 can be priority
controlled in slave mode via a 1-byte brightness value (communication
object: “Channel X - Set Brightness Value”). The “slave mode” is activated
and deactivated via the 1-bit communication object “Channel X - Slave
Operation On / Off”. Constant lighting control is possible with an appropriate
KNX device (e.g. LR/S 2.2.1), which as master supplies a 1-byte brightness
value as a control value.
The application data of the master device and the KNX bus load
must be taken into account.
With DALI, it is possible to monitor the DALI devices of a channel together
(in broadcast). With the DALI Gateway, it is possible to distinguish between
a lamp and a ballast fault. A fault is detected directly and displayed on the
gateway by the yellow LED. The information is simultaneously made availa-
ble via the KNX through a channel-related communication object and can
be sent to a control unit or visualisation program for display purposes. From
there, the necessary repair measures or corresponding maintenance cycles
can be initiated. The current status of the lighting installation in the building
is always available or can be retrieved on request. It is thus possible to inte-
grate the lighting in a higher-order Facility Management system.
Equipment with a DALI interface can send a DALI telegram which displays a
lamp fault. This information is queried by the DALI Gateway. The correspon-
ding data sheets of the device manufacturer state whether the DALI equip-
ment in use reports a lamp fault.
With the DALI-Gateway DG/S 8.1, it is possible to detect lamp
faults per channel. It is not possible to detect how many or which
of the max. 16 devices in the channel have a lamp fault.
Note: You can assume that in general all DALI ballasts support the reporting
of a lamp fault. DALI dimmers and DALI switch actuators often do not have
this characteristic.
To guarantee correct operation, the gateway must know how many ballasts
must be monitored. This is carried out by activating the object “Detect
Ballasts”. With this function, the DALI Gateway establishes automatical-
ly how many ballasts are connected and uses this number as a reference
value. If the installation should be extended or reduced, the option “Detect
Ballasts” must be activated again. This process is only necessary if the
number of ballasts per channel has changed and not when replacing a
ballast in the same channel.
The duration of the ballast detection is dependent on the number of connec-
ted DALI devices and can take approx. 1 minute with the maximum number
of devices.
3.6 Constant
lighting
control
3.7
Monitoring of lamps
and ballasts